Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:EXPT00572 (Asn)
 11,732 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

[3-beta-(2-Thienyl)-L-alanine]-8-lysine-vasopressin was synthesized by solution techniques. The partially protected heptapeptide Boc-Cys(Ec)-Tyr-Thi-Gln-Asn-Cys(Ec)-Pro (1) was synthesized in a stepwise manner using the active ester method or the dicyclohexylcarbodiimide (DCC) coupling technique mediated by 1-hydroxybenzotriazole (HBt). The protected nonapeptide amide Boc-Cys(Ec)-Tyr-Thi-Gin-Asn-Cys(Ec)-Pro-Lys(Coc)-Gly-NH2 (2) was prepared by coupling 1 with Lys(Coc)-Gly-NH2 using DCC-HBt. From 2, [3-thienylalanine]-8-lysine-vasopressin was obtained by removing the Boc-protecting groups with trifluoroacetic acid and ethylcarbamoyl (Ec) protecting groups in refluxing liquid NH3 followed by oxidative cyclization in H2O-MeOH using ICH2CH2I. Purification was effected by partition chromatography followed by gel filtration. The highly purified product possesses activities in the oxytocic, avian vasodepressor, rat pressor, and antidiuretic assays of 19.0 +/- 0.5, 87 +/- 4, 243 +/- 5, and 332 +/- 32 units/mg, respectively. Thus [3-thienylalanine]-8-lysine-vasopressin has higher oxytocic, avian vasodepressor, and antidiuretic potencies than does 8-lysine-vasopressin, whereas its pressor potency is about the same as or slightly lower than that of 8-lysine-vasopressin.
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PMID:Synthesis and some pharmacological properties of (3-beta-(2-thienyl)-L-alanine)-8-lysine-vasopressin. 117 84

The amino acid sequence for vitamin D-dependent bovine intestinal calcium binding protein has been established. It contains 85 amino acids in a single chain and lacks cysteine, tryptophan, methionine, histidine, and arginine. The NH2-terminal lysine is blocked by an N-acetyl group. Enzymatic digestion with trypsin, chymotrypsin, and pepsin yielded a number of peptides which were purified by two-dimensional high voltage paper electrophoresis. These peptides were examined by end group analysis and sequenced by the dansyl procedure. The absence of tryptophan permitted by a single cleavage of the molecule by N-bromosuccinimide at the tyrosine residue at position 8 and the larger fragment was subjected to automated Edman degradation. By these means, the following sequence was established: N-Ac-Lys-Gln-Ser-Pro-Leu-Glu-Tyr-Ala-Ala-Glu-Lys-Ser-Ile-Gln-Lys-Glu-Ile-Glu-Lys-Gly-Phe-Phe-Lys-Gln-Leu-Leu-Val-Ser-Val-Gln-Lys-Ala-Gly-Asp-Lys-Glu-Ser-Leu-Gln-Pro-Leu-Phe-Thr-Leu-Leu-Lys-Ser-Gly-Pro-Glu-Glu-Asn-Leu-Lys-Glu-Ser-Gln-Asn-Gly-Pro-Asp-Leu-Ls7-Ser-Gly-Pro-Gly-Asn-Asp-Leu-Glu-Glu-Lys-Gly-Thr-Asp-Val-Phe-Ser-Leu-Lys-Gln. Microheterogeneity may exist in the molecule at residue 76 in which position threonine may be replaced by serine. Comparison of the sequence of calcium-binding protein to the "test" sequence of Tufty and Kretsinger ((1975) Science 187, 167-169) proposed to identify E-F hands in muscle proteins suggests that intestinal calcium-binding protein may likewise contain one or possibly two E-F hands which could account for calcium-binding property. Dayhoff alignment scores, however, calculated for calcium-binding protein against nine E-F hands in muscle proteins parvalbumin, troponin and alkali light chains do not indicate that intestinal calcium-binding protein is homologous to these muscle protein chains.
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PMID:Calcium-binding protein of bovine intestine. The complete amino acid sequence. 117 41

A method is described for isolation, from chicken pancreas, of an avian pancreatic polypeptide which may be a new hormone. This method involves acid-alcohol extraction, gel filtration, DEAE-cellulose chromatography, and droplet countercurrent distribution. The peptide contains 36 amino acids, has a molecular weight of 4240 and the isoelectric point if pH 6 to 7. The average amount of avian pancreatic polypeptide extractable from chicken pancreas was 4 mg/100 g of pancreas. The amino acid sequence of the peptide is Gly-Pro-Ser-Gln-Pro-Thr-Tyr-Pro-Gly-Asp-Asp-Ala-Pro-Val-Glu-Asp-Leu-Ile-Arg-Phe-Tyr-Asp-Asn-Leu-Gln-Gln-Tyr-Leu-Asn-Val-Val-Thr-Arg-His-Arg-Tyr-NH2.
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PMID:Isolation and characterization of a new pancreatic polypeptide hormone. 119 89

The synthesis of the protected polypeptide precursor of [1-beta-mercapto-beta,beta-diethylpropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin was performed in a stepwise manner by solution techniques. This analog of oxytocin has two modifications, each of which taken alone gives analogs which inhibit some of the pharmacological responses to oxytocin. The S-ethylcarbamoyl protecting groups of beta-Mpa(beta-Et2)(Ec)-Dbt-Ile-Gln-Asn-Cys(Ec)-Pro-Leu-Gly-NH2 were removed in refluxing liquid NH3, and the resulting disulfhydryl compound was oxidatively cyclized in H2O-MeOH with ICH2CH2I. Purification was effected by partition chromatography and gel filtration. The analog possesses antioxytocic (pA2 = 7.08) and antiavian vasodepressor (pA2 = 7.38) activities but has neither agonist nor antagonist activity in the rat pressor assay. These potencies are close to those exhibited by [1-beta-mercaptopropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin but different from those of [1-beta-mercapto-beta,beta-diethylpropionic acid]oxytocin.
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PMID:Synthesis and some pharmacological properties of [1-beta-mercapto-beta,beta-diethylpropionic acid,2-(3,5-dibromo-L-tyrosine)]oxytocin. 119 81

The complete amino acid sequence of rat thyrocalcitonin has been determined by automated Edman degradations of the intact molecule, a cyanogen bromide fragment, and by degradations of mixtures of peptides produced by hydrolysis of the hormone with trypsin and chymotrypsin. The sequence determined was H2N-Cys-Gly-Asn-Leu-Ser-Thr-Cys-Met-Leu-Gly-Thr-Tyr-Thr-Gln-Asp-Leu-Asn-Lys-Phe-His-Thr-Phe-Pro-Gln-Thr-Ser-Ile-Gly-Val-Gly-Ala-Pro-NH2. This sequence differs in only two positions from that found in the human hormone, i.e. leucine-16 in the rat vs phenylalanine-16 in the human, and serine-26 in the rat vs alanine-26 in the human. These similarities and differences are consistent with the previously reported immunological properties of the hormones isolated from these two species.
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PMID:The complete amino-acid sequence of rat thyrocalcitonin. 127 75

A series of 24 peptides Z-Gly-Xaa(R)-OH where Xaa = 15 different residues and R = H, NH2, tBu, Bzl, Trt, Mtr, and StBu were coupled with valine benzyl ester in dimethylformamide or dichloromethane at +5 degrees. The accompanying racemization was determined by analysis of the epimeric products by normal phase high-performance liquid chromatography (HPLC) for Xaa(R) = Met, Cys(StBu) and Lys(Z) and by reversed-phase HPLC after removal of benzyl-based protecting groups for Xaa(R) = Ser(tBu), Thr(tBu) and Arg(Mtr). The coupling methods examined included mixed anhydride (MxAn) at -5 degrees, and N,N'-dicyclohexylcarbodiimide (DCC), benzotriazol-1-yl-tris(dimethylamino)phosphonium hexafluorophosphate (BOP) and O-benzotriazol-1-yl-N,N,N',N'-tetramethyluroniumhexafluorophosp hate (HBTU) in the presence of 1-hydroxybenzotriazole (HOBt). Very few couplings gave stereochemically pure products. The order of sensitivity to racemization of residues depended on the method of coupling and the solvent. It varied most when comparing MxAn to HOBt-assisted reactions; it varied moderately when comparing HOBt-assisted reactions. There was less variation in comparing BOP and HBTU reactions that are initiated by the same mechanism. Leu, Nle, Phe, Asn, Lys(Z) and Asp(OBzl) are identified as the residues least sensitive to racemization. DCC-HOBt generally led to less epimerization than the other methods.
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PMID:Studies on sensitivity to racemization of activated residues in couplings of N-benzyloxycarbonyldipeptides. 128 41

1. Extracellular recordings were made from 297 spontaneously firing neurones in the dorsal motor nucleus of the vagus (DMV) in slice preparations of rat medulla oblongata. Some of the neurones recorded were identified to be vagal motoneurones by antidromic stimulation. The cells fired with a slow irregular pattern at an average rate of 1.1 +/- 0.1 spikes/s (mean +/- S.E.M.). 2. Arginine vasopressin (AVP) was applied by perfusion in 196 of the 297 cells. Most of the neurones (190/196, 97%) were excited by 10(-6) M AVP with an increase in firing rate from the basal level of 1.1 +/- 0.1 to a maximum of 2.5 +/- 0.2 spikes/s. There was a dose-dependent relation between the concentration of AVP and the increased firing rate in all DMV neurones tested (n = 38). The threshold concentration of the peptide to produce changes in firing rate was assumed to be about 10(-10) M. The remaining six neurones were not affected by application of AVP. 3. Application of oxytocin (OXT, 10(-6) M) increased the firing rate of all thirty-eight neurones tested. The effects of AVP and OXT on all neurones examined (n = 20 and 4, respectively) still persisted after blocking the synaptic transmission in a low-Ca2+ or Ca(2+)-free-high-Mg2+ solution, indicating the direct action of both AVP and OXT on the postsynaptic membranes. 4. The AVP-induced excitatory responses were completely but reversibly blocked by the V1-type receptor antagonists, [1-(beta-mercapto-beta, beta-cyclopentamethylene-propionic acid), 2-(O-methyl)tyrosine]-arginine vasopressin (d(CH2)5Tyr(Me)AVP) (n = 5) and Phaa-D-Tyr(Et)Phe-Gln-Asn-Lys-Pro-Arg-NH2 (n = 6), whereas a selective and reversible OXT receptor antagonist, desGly-NH2d(CH2)5[Tyr-(Me)2Thr4]ornithine vasotocin, which suppressed the OXT-induced excitation, did not block the responses to AVP (n = 11). 5. Application of angiotensin II (AII, 10(-6) M) to 153 neurones increased the firing rates of 60 (39%) neurones. The firing rate was increased from the basal level of 1.0 +/- 0.1 to a maximum of 1.8 +/- 0.2 spikes/s (n = 60). The effect of AII was completely abolished by an AII receptor antagonist, [Sar1,Ile8]angiotensin II (n = 6). There was a dose dependence of the excitatory response on AII concentration in all of eleven neurones tested. The threshold concentration was assumed to be about 10(-9) M. The activity of 5 (3%) of 153 neurones was decreased, and the remaining 88 (58%) neurones were not affected by AII.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Effects of vasopressin and angiotensin II on neurones in the rat dorsal motor nucleus of the vagus, in vitro. 130 79

Ac-Tyr298-Ala299-Gly300-Thr301-Val302-I le303-Asn304-Asp305-Leu306-OH (Ac-VZV R2-(298-306)) represents the acetylated form of the C-terminus of varicella-zoster virus (VZV) ribonucleotide reductase subunit 2 (R2). This peptide possesses a high degree of homology with the C-terminus nonapeptide of the herpes simplex virus (HSV) type I and II ribonucleotide reductase R2 protein and is 15 times more potent than the latter in its in vitro inhibition of HSV-1 reductase activity. Accordingly, a new series of analogues based on this structure was studied in vitro. The replacement of Asp305 by Asn, Glu, Gln, Ser, or Cys; of Asn304 by Gln or Ser; of Ile303 and Val302 by D-Val; and of Tyr298 by Cha induced an important loss of inhibitory potency. The substitution of Asn304 by Asp; of Thr301 by Cys, Ser, or Val; of Gly300 by Ala or Val; of Ala299 by Val; or of Tyr298 by homoPhe, 4'-fluoro-Phe, 4'-chloro-Phe, 3'-iodo-Tyr, Me-Tyr, or For-Trp led to a moderate decrease of the Ac-VZV R2-(298-306) potency. The replacement of Val302 by Ile; Ala299 by Cys, Ser, or Thr; or the insertion of a six- or eight-carbon chain between Tyr298 and the NH2 terminus either preserved or slightly increased the inhibitory potency of Ac-VZV R2-(298-306). Finally, the substitution of Tyr298 by Trp or the addition of 4'-nitro-Phe at the amino terminus resulted in a 3-fold increase of potency. Altogether, these results stress the importance of the structural integrity of the minimum active core 302-306 in preserving the inhibitory potency and suggest that further studies on monosubstitutions could be directed at the portion 298-301 of the peptide.
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PMID:Structure-function studies of peptides inhibiting the ribonucleotide reductase activity of herpes simplex virus type I. 131 Jan 20

The N- and C-terminally protected peptide N-acetyl-Asp-Phe-Ala-Asn-Arg-Val-Leu-Leu-Ser-Leu-Phe-Thr-Ile-Glu-Met-Leu -Leu-Lys-Met-Leu-NH2, closely based on the sequence of the putative S2 membrane spanning helix of domain II of the dihydropyridine receptor calcium channel of the T-system of skeletal muscle, residues 465-486 (Tanabe et al. (1987) Nature 328, 313-318) has been synthesised. Conductance measurements in planar lipid bilayers show that the peptide is capable of inducing the transmembrane passage of calcium and barium ions, in preference to monovalent cations. No anion conductance is observed. 1H-NMR spectroscopy demonstrates that in an amphilic solvent, methanol, the peptide forms highly stable structures characterised by very slow exchange with solvent of peptide N-H protons. Double-quantum filtered phase-sensitive COSY shows that, on the basis of NH-CH alpha scalar coupling constants, most peptide torsion angles are appropriate to an overall alpha-helical conformation; the presence of some alpha-helix is also supported by CD measurements. Most side-chain connectivities have been identified in a DIPSI-TOCSY experiment. This evidence has been used to construct a low-resolution model of the ion-conducting channel of the muscle T-system dihydropyridine receptor from the sequences of the four homologous putative channel-lining stretches. It is characterised by an association of acidic residues at the putative extra-membranous face of the channel, followed by a predominantly hydrophobic band. The next prominent feature of the model is an ordered array of four acidic residues (glutamates 100, 478, 846 and 1164), followed by four lysines (104, 482, 850 and 1168) which may play a gating role.
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PMID:An electrophysiological and spectroscopic study of the properties and structure of biological calcium channels. Investigations of a model ion channel. 131 22

Peptides that are derived from the processing of proopiomelanocortin were isolated in pure form from the brain of the frog Rana ridibunda. The primary structure of the most abundant of those peptides was established as: Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val. This amino acid sequence is identical to that of mammalian and frog pituitary alpha-melanocyte-stimulating hormone (MSH) and the peptide co-eluted with synthetic desacetyl alpha-MSH, indicating that it is COOH-terminally alpha-amidated. A second component, which exhibited a shorter retention time, co-eluted with the glycine-extended form of desacetyl alpha-MSH [ACTH(1-14)]. The primary structure of the third peptide isolated in pure form from the brain extract was established as: Lys-Tyr-Val-Met-Ser-His-Phe-Arg-Trp-Asn-Lys-Phe-NH2. This sequence corresponds to Lys-gamma 1-MSH as predicted from the nucleotide sequence of frog proopiomelanocortin. The presence of substantial amounts of desacetyl alpha-MSH and Lys-gamma 1-MSH in the frog brain supports the concept that, in amphibia, melanotropins may act as neurotransmitters and/or neuromodulators as well as hormonal peptides.
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PMID:Isolation and structural characterization of peptides related to alpha- and gamma-melanocyte-stimulating hormone (MSH) from the frog brain. 133 55


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